A steering knuckle of an automobile is a very important component for the automobile, its machining process is very complex, and different components are mounted in different holes of the steering knuckle in a combination manner. Therefore, the position accuracy of each hole is very important. In order to monitor whether the position accuracy of each hole is qualified during production, currently a position accuracy comprehensive checking fixture is utilized in the industry. Such checking fixture has higher detection efficiency and is more convenient to detect compared with a three-coordinate measuring machine.